They further looked at testosterone levels in the kids and followed them through early childhood. The children, girls included, who higher levels of testosterone were slower learning communication skills and had more interest in mechanical things.

Oxygen alone does not make an insect (let alone anything) bigger. That dragonfly got that big probably because there were no natural predators for it. There's a cricket in the mountains of South America that can get pretty big for those exact reasons.

Agree wholeheartedly. Also to add, Celsius isn't REALLY metric. It's just part of the metric system by arbitrary decision. Another thing is, Fahrenheit's 100 was originally set to be about the average human body temperature. Even today, it's easy to tell that if you have a temp over 100 you probably are sick. Setting the bounds of 0-100 based on when water freezes and cools is incredibly arbitrary honestly. As water boils at different temps based on atmospheric pressure. Lastly, Rankine units. If you want to get into science and math, Rankine I think is better than Kelvin. Why? Same bound for 0 (absolute), but the units are the higher resolution Fahrenheit. Better precision, means less fractions, easier to do math with.